Process for treating hydrocarbon oils



Sept. 16, 1930. w. S/HADAWAY, JR 1,776,023

PROCESS FOR TREATING HYDROCARBON OILS Filed May 16. 1927 avweuto ASMSH Patented Sept. 16, 1930 I UNITED STATES PATENT OFFICE WILLIAM S. HADAWAY, JR, NEW ROCHELLE, NEW YORK, ASSIGNOB TO THE TEXAS COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE PROCESS FOR TREATING HYDBOCARBON OILS Application filed May 16, 1927. Serial No. 191,596.

' combustion gases are employed as the heating medium and my invention seeks to apply electric heating in the treatment of hy drocarbon oils in a certain novel and useful way.

My invention contemplates a process wherein the oil is heated a certain amount and then passed through an electrically heated conduit to thereby raise the oil to the final temperature desired.

The invention has special relation to continuous processes and contemplates the passing of the oil through a coil or a tubular heater wherein the bulk of the heat desired is applied and then passing the oil through an electrically heated conduit with such control of the electric heating elements that the oil may be discharged from this conduit at a substantially constant temperature. In other words, in the practice of my invention I rely mainly on the primary heater for supplying the bulk of the heat to the oil and use an auxiliary electric heater for applying the final increment of heat desired or for merely controlling the temperature in such a way as to obtain the temperature desired. The

oil after having been thus brought to this temperature may then be discharged into an enlarged chamber for distillation or digestion.

My invention has special application to the treatment of hydrocarbon oils at elevated temperatures and pressures for the conversion of higher boiling hydrocarbons into lower boiling ones and the production of volatile distillates, such as gasoline. In carrying out my invention the oil is passed through a high pressure coil located in a suitable furnace, in which coil the oil is heated to a cracking temperature. The heated oil is then passed through an electrically heated conduit and the electric heating means is accurately controlled to apply to the oil such degree of heating as may be necessar to maintain in the stream of oil issuing om the electrically heated conduit the constant temperature desired. The heated oil is then discharged into an enlarged chamber maintained either with or without distillation wherein the oil is maintained under superatmospheric pressure and at the cracln'ng temperature desired. The enlarged chamber may be insulated to prevent loss of heat through radiation or it may be encased in a furnace or heating chamber arranged to apply such heat as is necessary to maintain the body of oil therein at the desired cracking temperature. A plurality or battery of converters may be used if desired.

In order to more fully explain the invention, reference will now be had to the accompanying drawing which illustrates in diagrammatic sectional elevation a specific embodiment of the invention.

In the drawing 10 designates a heating coil positioned in a furnace 11 provided with a burner 12. The oil to be treated is drawn from a suitable pump 13 and introduced through the charging line 14. into the coil 10. A transfer line 15 connects the coil 10 to an electrically heated coil 16 and a transfer line 17 connects the latter coil with a still or con verter 18. i

' The coil 16 is suitably disposed about an electric heating element 19 and the heating element and coil are suitably encased in an insulating jacket or cover 20. Conductors 21 connect the heating element 19 with a suitable source of electric energy not shown through a regulator or contact making and breakmg apparatus 22. A thermo-sensitive element 23 is associated with the transfer line 17 and is adapted to control the operation of the regulator 22 in such a way that the making and breaking of the electrical contacts is made in response to temperature fluctuations of the oil in the transfer line 17. The regulator is not described in detail herein since any suitable regulator may be employed and various types are well known. In dotted lines is indicated an alternative arrangement wherein instead of employing automatic regulation of the heating applied to the coil 16, the heating may be manually controlled by means of a transformer 24.

' The still 18 is shown as being insulated and as being provided with scrapmg or stirring elements 25 carried on a shaft 26 and with a motor 27 for operating the shaft. The still is also equipped with a tar or residue drawofi 28 with a vapor line 29 which extends to a preliminary condenser or 'fractionating or dephlegmating apparatus 30. A vapor line 31 extends to a condenser coil 32 and a reeeiving drum 33, equipped with a valved gas line 34 and a valved distillate line 35, is provided to receive the condensate from the condenser. A backtrap or reflux condensate line 36 is provided for drawing off liquid from the fractionating or dephlegmating apparatus 30 and a pump 37 operates to charge this material through the pipe 38 and thence into the heating coil 10.

The drawing shows a by-pass line 39 which connects the transfer line 15 with the transfer line 17 so that oil may be passed directly from the coil 10 into the still 18 without going through the coil 16, appropriate valves 40, 41, 42 being provided. This by-pass line is: provided so that in case during a run the temperature in the transfer line 15 should exceed the temperature desired in the oil to be delivered to the still 18, the coil 16 can thus be by-passed for a time until the temperature of the oil leaving the coil 10 has been reduced. The two-way passage between the heating coil 11 and still 18 serves the further function of permitting the regular passage of oil from the coil to the still through two passages one of which is unheated and the other of whic may be subjected to heating.

In one way of applying the invention to the conversion or cracking of oil with the particular apparatus illustrated, the oil charge after having been first preheated, if desired,

heatexchange with the hot tar or residue from the system or by heat exchange with the vapors or by other suitable means, is introduced into the heating coil 10 and brought to a cracking temperature. The oil is charged continuously from the coil 10 and thence through the electrically heated coil 16. It is preferable to supply the great bulk of the heat required bythe furnace 11 and apply with the heating element 19 only a relatively-small quantity of added heat, preferably only enough to enable the latter heating means to be employed as substantially a control means to accurately regulate the temperature of the oil discharged through the transfer line 17 into the still or converter 18. Thus, for example, the oil entering the transfer line 15 may be held at a temperature of say 800 F. or 810 F. or 840 F. and addi tional heat is supplied to the coil 16 so that the oil delivered to the coil 17 is at a temperature of say 850 F. While obviously the temperature margin between the oil in the trans fer lines 15 and 17 may vary Within comparatively wide elements, it is preferable,

as stated, that the great bulk of the heating be applied bythe furnace 1150 that the c011 16 will not be required to do any great amount of heating, its function being primarily that of a control device, and in the example given where it is desired to have an outlet tem rature in the transfer line 17 of 850 F. it is preferable to raise the temperature of the oil entering the transfer line 15 to say 840 F.

. The rate of charge of the oil throu h the coil 10 and the heating applied in the mace 11 is controlled as accurately as maybe so that the oil is brought to a temperature approaching that. desired for delivery into the cracking .vessel 18 and the final increment of heat is added in the electrically heated coil 16 which somewhat. lower than that in the transfer line 17 due to the decomposition and distillation which occur therein and thus, for example, with the temperature stated above of850 F. in the transfer line 17, the still 18 may be held at a temperature of about 775 F. It is,

of course, to be understood that the specific temperatures mentioned herein have been given merely for example. If desired the still or conversion chamber may be heated i and maintained at a temperature even higherthan that of the transfer line. Tar or residue is drawn off from the stillthrough the line 28 while the vapors are passed to the, fractionating or dep heavier roducts bein returned to the heat: the pump 3 The lighter vapors pass ,to e condenser .32 and-the resultant gas or other light distillateis collected in the receiver 33. v

In some cases it is desirable instead of passing all of the charge throu h the electrically heated coil 16 to divide t e charge issuing from the coil 10 and pass a portion through the heating coil 16 and the other portion directly through the line 39 into the transfer line 17 a proportion of oil passing through the coil 16 and the amount of heat applied thereto being controlled so that the tempera ture of the combined stream of oil charged into the still 18 will be held at the desired point.

Although my invention is of particular utility in its application to the cracking of hydrocarbon oils, it is also Well adapted for use in processes. the object of which. is merelegmating apparatus 30,-thestill or vaporizer, the vaporization taking place, if desired, under reduced pressure to that obtaining in the coil. By providing the electrically heated coil intermediate the main heating coil and the distilling chamber, it is possible to obtain a very accurate regulation of the stripping operation.

Obviously, various modifications'of the invention may be efiected without departing from the spirit and scope of the invention.

' The true scope of the invention is defined in the appended claim.

What I claim is: The process of converting high boiling hydrocarbon oils into lower boiling hydrocarbon oils, that consists in supplying thebulk of the necessary heat for the cracking reaction to the oil as it passes through a high temperature coil heated by a furnace which is not adapted for close regulation and supplying a so relatively small regulated increment of additional heat to the oil by immediately passing the hot oil from said coil through an electrically heated tube and regulating the electric heat input to maintain a predetermined outlet temperature.

In witness whereof I have hereuto set my hand this 5th day of May, 1927.

WILLIAM S. HADAWAY, JR. 

